Many of the electronic systems that are present on an airplane are temperature sensitive and prone to premature failure if subjected to extreme heat. For this reason, airplanes must have cooling systems that maintain a reasonable temperature within the airplane while it is not in use in order to maintain the integrity of the electronic systems aboard the airplane. Most modern day airport terminals have cooling systems that can be attached to an airplane to regulate its temperature while it is parked at the airport terminal. However, self-contained, on-board cooling systems are carried on airplanes to cool the electronic systems in cases where an external cooling system is not available, for example, when the airplane is not parked at a terminal or is parked at a terminal where an external cooling system is not present. On-board cooling systems typically utilize large, petroleum-based motors for operating the cooling system and any other systems on the airplane that require power. However, such systems are not efficient, as the motors must run for one to two hours in order to sufficiently cool the electronic systems on board the airplane. Consequently, the operation of petroleum-based motors in connection with airplane cooling can be very expensive and is therefore undesirable in the aviation industry.
As an alternative to petroleum-based motors, electrical motors have been used to power cooling systems on airplanes. However, electrical cooling systems produce heated exhaust air, which must be vented from the airplane. When an airplane is retrofitted so that an electrical cooling system may be installed, an exhaust vent must be added to the airplane. While the vent must be able to open to vent cooling system exhaust, the vent needs to remain sealed while the airplane is in flight so that cabin pressure is maintained. Although it is known to provide vents that may be manually sealed prior to takeoff, this creates an additional, and therefore undesirable, task for the crew. Furthermore, having a new opening in the fuselage of the airplane for an exhaust vent constitutes a design change for which the air-worthiness of the airplane must be revalidated. Thus, the expense of such a design change would outweigh the benefits obtained by using electrically operated cooling systems, as opposed to petroleum-operated cooling systems, and therefore, such a design change is not warranted.
It would be desirable to provide an aircraft exhaust vent assembly that automatically seals when not in use. It would also be desirable to provide an aircraft exhaust vent assembly that can be installed in an aircraft while avoiding recertification and revalidation of the aircraft.